Re: [Qemu-devel] Re: [PATCH 2/3] virtio network device

[Paul Brook]

> > Actually according to qemu's standard, one should use
> > cpu_physical_memory_write/ cpu_physical_memory_read functions.
> > This is true also for reading the ring values.
>
> Yes, and unfortunately, cpu_physical_memory_{read,write} are copy
> interfaces.  We really don't want that for high speed I/O.

I really don't like doing direct access to guest ram without implementing a 
proper API for zero-copy/scatter-gather access. There was a list thread about 
this not so long ago.

Paul